Compositions of enriched central nervous system stem cell and progenitor cell populations

Patent Number: 7,153,686

This patent covers a "Neurosphere Initiating Cell" isolated by its expression of the marker CD133. CD133 is expressed in a variety of stem cells and was recently shown to be found on cancer stem cells as well.

Essentially, neurospheres are aggregates of neural cells that are grown in tissue culture. Generally neurospheres are generated from fetal brain and spinal cord tissue homogenates that are placed in tissue culturewith components such as EGF, FGF-2 and LIF. Cells from fetus' of 5-12 weeks gestational age are capable of initiating neurospheres effectively. In contrast, cells from gestational ages of 16-20 weeks are less effective.

In the patent it states that brain cells from a fetus of 18 weeks gestational age are not able to induce neurospheres, but if neurosphere culture initiating cells are purified based on expression of CD133, then it is possible to generate neurospheres even at this late stage.

Essentially, the implications of identifying and patenting the cell capable of initiating neurospheres are that these cells can be used as a source of neural stem cells for treating diseases ranging from multiple sclerosis, to stroke, to Alzheimer's.

It should be noted that the assignee company, StemCells Inc is currently performing a clinical trial for an infantile metabolic disorder using, what they call, "Human central nervous system stem cells (HuCNS-SC)." We wonder if these cells are CD133+ purified?

One question that we wonder is whether the cells generated from whole brain fetal homogenate are indeed capable of regenerating all areas of the adult brain, or whether there is a level of stem cell specificity in that some stem cells can regenerate only certain parts of the brain.

View this patent on the USPTO website.